Fire extinguishing apparatus



July 7, 1964 R. A. GORSKI FIRE EXTINGUISHING APPARATUS Filed June 26, 1961 FlG.1

ROBERT ALEXANDER GORSKI INVHNTOR BY MW 6. WM

ATTORNEY United States Patent 3,139,934 FIRE EXTINGUISHING APPARATUS Robert Alexander Gorski, Newark, Del., assignor to E. L du Pont de Nemours and Company, Wilmington, Del., a corporation of Delaware Filed June 26, 1961, Ser. No. 119,519 Claims. (Cl. 169-31) This invention relates to fire extinguishers and particularly to liquified-gas type extinguishers. More particularly it relates to a novel nozzle and horn assembly for such fire extinguishers.

Halogenated aliphatic compounds, particularly bromotrifluoromethane, are known to be highly efiicient fire extinguishing agents. The halogenated aliphatic compounds at low temperatures and under substantial pressure remain liquid with minimum vapor pressure. Upon release of the gas pressure the liquid forms an extinguishing gas which is particularly useful for combating Class B fires. Class B fires are defined by National Fire Protective Associations Handbook of Fire Protection, 11th edition, 1954, 769, as fires in flammable liquids, greases, etc., Where a blanketing effect is essential. It has been found, however, that not all fire extinguishers are practical for dispensing halogenated aliphatic extinguishing agents.

An object of this invention is to provide an improved fire extinguishing apparatus which elficiently and effective ly dispenses halogenated aliphatic extinguishing agents. Another object of this invention is to provide such an extinguishing apparatus having nozzle and horn members possessing certain critical relationships to each other. Still further objects will be apparent from the following description.

The fire extinguishing apparatus of this invention comprises a container adapted to contain a halogenated aliphatic compound under pressure, a valve for releasing the contents of the container, a nozzle member terminating in a restrictive orifice and a horn member attached to said valve for directing and controlling the discharge of said contents, said extinguisher characterized by having a rate of discharge per orifice cross-sectional area of 1,400 to 3,000 grams per second per square centimeter, a horn diameter to orifice diameter ratio of 2.9 to 12, a rate of discharge to horn cross-sectional area of 20 to 185 grams per second per square centimeter, a horn length to horn diameter ratio of 2.6 to 30 and a restrictive orifice length to orifice diameter ratio of 0.5 to 10.

The fire extinguishing apparatus will now be more fully described with reference to the accompanying drawing which forms a part of this application. In the drawing, the same reference numerals refer to the same parts throughout the several views. With reference to the drawing FIG. 1 is a side elevational view of the apparatus,

FIG. 2 is a sectional View of the nozzle and horn assernblies of the apparatus taken substantially along line A-A of FIG. 1, and

FIG. 3 is a sectional view taken substantially along line BB of FIG. 2.

- The fire extinguishing apparatus, as illustrated in the drawing, comprises a conventional container 1 equipped with a dip tube (not shown) which contains liquified-gas halogenated aliphatic extinguishing agents such as bromotrifiuoromethane under pressure. A valve housing 2 having a conventional valve seat and closure (not shown) therein is attached to the container 1. The valve housing is fitted with a handle member 3 for opening and closing the valve. The valve housing has a projecting portion 4, Which is threaded to receive a nozzle member 5, terminating in a restrictive orifice 6. The nozzle member which is preferably fabricated from metal, e.g., steel, brass, etc., has a threaded bore 7 therein for reception of the threaded projecting portion 4 of the valve housing. The outer surface of the nozzle member has a plurality of flat surfaces 8 which may be gripped by a wrench or similar tool for securing the nozzle member to the projecting portion 4 of the valve housing. A horn member 9 is attached to the nozzle member, e.g., by a press fit, by brazing, etc. The horn member may also be an integral part of the nozzle. The horn may be fabricated from metal, e.g., aluminum, brass, etc., or of a suitable plastic.

In operation, when the valve is opened by turning handle member 3 the liquid halogenated aliphatic compound in the container 1 passes through the valve and is released through restrictive orifice 6 and down the horn member 9 onto a flammable liquid or grease fire thereby smothering the flames. It is critical to the effective, efficient operation of the halogenated, aliphatic compoundcontaining extinguishing apparatus that the following structural and operational relationship be maintained within the limits specified.

(1) The discharge rate of extinguishing agent from restrictive orifice 6 to the cross-sectional area of the orifice ranges from 1,400 to 3,000 g. sec.- Cm.

(2) The inner diameter D of horn member 9 to the diameter d of orifice 6 ranges from 2.9 to 12 (the diameters D and d are shown in FIG. 2).

(3) The discharge rate of extinguishing agent from restrictive orifice 6 to the cross-sectional area of horn member 9 ranges from 20 to 185 g. sec. cm.-

(4) The length L of horn member 9 to the inner diameter D of the horn member ranges from 2.6 to 30 (the length L and diameter d are shown in FIG. 2).

(5) The length l of restrictive orifice 6 to the diameter d of the orifice ranges from 0.5 to 10, preferably from 0.5 to 2 (the orifice length l and diameter d are shown in FIG. 2).

The invention will be illustrated by but is not intended to be limited to the following examples which were performed using a naphtha fire pan which was fabricated to meet the Underwriters Laboratory, Inc., specifications for a 6B fire. The dimensions of the fire pan were: 1 foot in height, 3.872 feet in length and 3.872 feet in width, giving a surface area of 15 square feet. In the pan was placed water to a depth of 4 inches and on top of the water 2 inches of naphtha. The naphtha was ignited and was allowed to burn for 60 seconds prior to attack by the fire extinguishing agent. The fire extinguisher utilized in the examples consisted of an cubic inch capacity extinguisher containing 2% pounds of bromotrifluoromethane and was pressured with nitrogen to a total pressure of 380 p.s.i.g. at about 70 F In extinguishing the fires, the horn member was placed at about a 45 angle with respect to the extinguisher cylinder. The horn member was aligned with the two diagonal corners of the pan at a position about 2 to 3 feet from the pan and about 5 feet above the base of the pan. The extinguishing agent was directed initially toward the burning fuel surface in the nearest corner of the pan. As the flames were extinguished, the agent was directed back and forth across the pan at the flame front proceeding toward the further corner until the flames were entirely extinguished. As extinguishment proceeded, the horn member was maintained at the five foot height level but was moved to approximately one foot from the corner of the pan when it was feasible for the operator to do so.

Example 1 Two hand fire extinguishers of the type described above having a discharge rate of about g. sec.- an orifice having a diameter (d) of 0.326 cm., a horn member having an inner diameter (D) of 1.35 cm. and a length (L) of 23.32 cm., one of said extinguishers having a restrictive orifice length (l) of 0.397 mm. and the other extinguisher having an'orifice length (l) of 1.59 mm. were used on the naphtha pan fire in the manner described above. The extinguishers had the following critical relationships:

(1) A discharge rate of extinguishing agent to cross-sectional area of the orifice of 1,436 g. sec. cur- (2) A diameter of the horn member to the diameter of the orifice of 4.13,

(3) A discharge rate of extinguishing agent to cross-sectional area of the horn member of 74.9 g. sec? cm.-

(4) A length of horn member to diameter of the horn member of 17.3,

(5) A length of orifice to diameter of the orifice of 1.217'and 4.88.

All fires attacked with the above-described extinguishers were extinguished in 5.4 to 9.1 seconds.

Example 11 Example I was repeated utilizing an extinguisher having the following physical characteristics:

A discharge rate of about 107 g. secf an orifice having a diameter of 2.82 mm., an orifice length of 1.59 mm., a horn member having an inner diameter of 1.35 cm. and a length of 23.32 cm. The extinguisher had the following critical relationships:

(1) Adischarge rate of extinguishing agent to cross-sectional area of the orifice of 1,714 g. SBC.1 cmf (2) A diameter of the horn member to the diameter of the orifice of 4.78,

(3) A discharge'rate of extinguishing agent to crss-sectional area of the horn member of 83.7 g. sec? Cm.

(4) A length of horn member to diameter of the horn member of 17.3,

( A length of orifice to diameter of the orifice of 0.564.

All fires were extinguished with this apparatus in from 6.1 to 8.8 seconds.

Example III Example I was repeated utilizing an extinguisher having the following physical characteristics:

A discharge rate of about 100 g. SCCI'I, an orifice having a diameter of 2.70 mm., an orifice length of 1.59 mm., a horn member having an inner diameter of 1.35 cm. and a length of 23.32 cm. The extinguisher had the followingcritical relationships:

(1) A discharge rate of extinguishing agent to cross-sectional area of the orifice of 1,755 g. sec? cmf (2) A diameter of the horn member to the diameter of the orifice of 4.98,

(3) A discharge rate of extinguishing agent to cross-sectional area of the horn member of 70.45 g. sec? Cm.

(4) A length of horn member to diameter of the horn member of 17.3,

( 5 A length of orifice to diameter of the orifice of 0.59.

All fires were extinguished with this apparatus in from 4.5 to 7.0 seconds.

Example IV Example I was repeated utilizing an extinguisher having the following physical characteristics:

A discharge rate of about 90 g. seean orifice having a diameter of 2.37 mm:, an orifice length of 1.59 mm, a horn member having an inner diameter of 1.35 cm. and a length of 23.32 cm. The extinguisher had the following critical relationships:

(1) A discharge rate of extinguishing agent to cross-sectional area of the-orifice of 2,040 'g. sec. cmf

(2) A diameter of the horn member to the diameter of the orifice of 5.7,

(3) A discharge rate of extinguishing agent to cross-sectional area of the horn member of 62.9 g. SC. 1, Cm.

(4) A length of horn member to diameter of the horn member of 17.3,

(5) A length of orifice to diameter of the orifice of Eight fires were extinguished with this apparatus in from 8 to 9 seconds.

Example V Example I was repeated utilizing an extinguisher having the following physical characteristics:

A discharge rate of 60 g. sec. an orifice having a diameter of 0.1613 cm., an orifice length of 0.1588 cm., a horn member having an inner diameter of 0.792 cm. and a length of 23.32 cm. The extinguisher had the following critical relationships:

(1) A discharge rate of extinguishing agent to crosssectional area of the orifice of 2,940 g. sec.- CH1. 2,

(2) A diameter of the horn member to the diameter of the orifice of 4.91,

(3) A discharge rate of extinguishing agent to crosssectional area of the horn member of 122 g. secr cm.-

(4) A length of horn member to diameter of the horn member of 29.5,

(5) A length of orifice to diameter of the orifice of 0.985.

All fires were extinguished with this apparatus in from 5 to 10 seconds.

Example VI Example I was repeated utilizing an extinguisher having the following physical characteristics:

A discharge rate of 81 g. SCC. 1, an orifice having a diameter of 0.2183 cm., an orifice length of 0.1587 cm., a horn member having an inner diameter of 0.792 cm. and a length of 23.32 cm. The extinguisher had the following critical relationships:

(1) A discharge rate of extinguishing agent to crosssectional area of the orifice of 2,160 g. seecmr (2) A diameter of the horn member to the diameter of the orifice of 3.63,

(3) A discharge rate of extinguishing agent to crosssectional area of the horn member of g. sec.- CIIISZ,

(4) A length of horn member to diameter of the horn member of 29.5,

(5) A length of orifice to diameter of the orifice of 0.727.

All fires were extinguished with this apparatus in from 5 to 10 seconds.

Example Vll Example I was repeated utilizing an extinguisher having the following physical characteristics:

A discharge rate of 102 g. secf an orifice having a diameter of 0.2708 cm., an orifice length of 0.1588 cm., a horn member having an inner diameter of 1.349 cm. and a length of 8.09 cm. The extinguisher had the following critical relationships:

All fires were extinguished with this apparatus in from 5 to 10 seconds.

Example VIII Example I was repeated utilizing an extinguisher having the following physical characteristics:

A discharge rate of about 100 g. secan orifice having a diameter of 3.27 mm., an orifice length of 1.905 cm., a horn member having an inner diameter of 1.905 cm. and a length of 11.44 cm. The extinguisher had the following critical relationships:

(1) A discharge rate of extinguishing agent to crosssectional area of the orifice of 1,193 g. sec.- cmf (2) A diameter of the horn member to the diameter of the orifice of 5.83,

(3) A discharge rate of extinguishing agent to crosssectional area of the horn member of 35.1 g. SC. 1 cm.

(4) A length of horn member to diameter of the horn member of 6.0,

(5) A length of orifice to diameter of the orifice of 5.83.

This extinguisher apparatus falls outside the scope of this invention. All attempts to extinguish fires with the extinguisher failed.

The above examples illustrate the criticality of the enumerated relationships (1 to 5). If one or more relationships fall outside the specified limits, the extinguisher loses its efiectiveness against flaming liquid fires. Specifically, if the rate of discharge to the cross-sectional area of the orifice is greater than is specified, the velocity of the discharge is too high. The high discharge velocity agitates the surface of the burning liquid and makes extinguishment much more difficult if not impossible. When the rate of discharge to the cross-sectional area of the orifice is less than the range enumerated, the velocity of the discharge is too low and all attempts to extinguish fires of the type described in the examples fail.

A ratio of horn diameter to orifice diameter less than the specified range results in a jetting efiect which yields results similar to the rate of discharge to the cross-sectional area of the orifice being above the limits specified. On the other hand, when the horn diameter to orifice diameter ratio is too large, the extinguishing agent condenses due to cooling from expansion and runs from the end of the extinguisher horn as a liquid.

A rate of discharge to the cross-sectional area of the horn that is below the range specified results in the carrying distance of the extinguishing agent being decreased and poor extinguisher performance being obtained. If the ratio is above the limit specified, the velocity of the discharge is too high and results in severe and undesirable agitation of the surface of the flammable liquid.

If the horn length to horn diameter exceeds the specified limits, the extinguishing agent condenses due to cooling from the expansion and runs from the end of the horn as a liquid; the effective range of extinguishing agent is thereby reduced. A smaller ratio than specified makes directing of the discharging agent difficult, as the agent spreads over too great an area; the eflective range of the extinguishing agent is thereby reduced.

The novel fire extinguisher of this inveniton is particularly useful with bromotrifluoromethane fire extinguishing agent in putting out flammable liquid and grease fires in an extremely short period of time. The extinguisher is also useful with other halogenated aliphatic compound extinguishing agents, e.g., dibromodifluoromethane, 1,2- dibromotetrafluoroethane, trichlorofluoromethane and mixtures of these with other materials such as chlorotrifluoromethane or dichlorodifluoromethane. While the apparatus is generally used in its portable, hand-carrying embodiment, larger extinguishers utilizing the concepts of this invention are practicable.

An advantage of the apparatus of this invention is that it is extremely efiicient and eifective against fires resulting from flammable liquids and greases (Class B). Another advantage of this invention is that the apparatus utilizes commercially available components. A further advantage is that the apparatus is cheap and simple to construct and is easy to operate. Still other advantages will be apparent from the foregoing description.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a fire extinguisher, a container adapted to contain a liquified halogenated aliphatic gaseous compound under pressure, a valve for releasing the contents of the container, a nozzle member attached to said valve, said nozzle member terminating in a restrictive orifice, said restrictive orifice having a ratio of orifice length to orifice diameter of 0.5 to 10 so that said extinguisher has a rate of discharge per orifice cross-sectional area of 1,400 to 3,000 grams per second per square centimeter, a horn member attached to said nozzle member, said horn member having a ratio of horn length to horn diameter of 2.6 to 30 and a ratio of horn diameter to orifice diameter of 2.9 to 12 so that said extinguisher has a rate of discharge per horn cross-sectional area of 20 to grams per second per square centimeter, whereby opening the valve causes the liquified halogenated aliphatic gaseous compound to pass through said restrictive orifice and be expelled from said horn as a fire smothering gas.

2. A fire extinguisher as defined in claim 1 wherein the ratio of the length of the orifice restriction to orifice diameter is 0.5 to 2.

3. A fire extinguisher as defined in claim 1 wherein said horn member is an integral part of said nozzle.

4. In a fire extinguisher, the combination comprising, a liquified halogenated aliphatic gaseous compound under pressure, a container adapted to hold said aliphatic compound, a valve for releasing the contents of the container, a nozzle member attached to said valve, said nozzle member terminating in a restrictive orifice, said restrictive orifice having a ratio of orifice length to orifice diameter of 0.5 to 10 so that said extinguisher has a rate of discharge per orifice cross-sectional area of 1,400 to 3,000 grams per second per square centimeter, a horn member attached to said nozzle member, said horn member having a ratio of horn length to horn diameter of 2.6 to 30 and a ratio of horn diameter to orifice diameter of 2.9 to 12 so that said extinguisher has a rate of discharge per horn crosssectional area of 20 to 185 grams per second per square centimeter, whereby opening the valve causes the liquified halogenated aliphatic gaseous compound to pass through said restrictive orifice and be expelled from said horn as a fire smothering gas.

5. In a fire extinguisher as defined in claim 4 wherein the aliphatic compound is bromotrifluoromethane.

Justis Apr. 10, 1951 Beauregard Dec. 16, 1952 

1. IN A FIRE EXTINGUISHER, A CONTAINER ADAPTED TO CONTAIN A LIQUIFIED HALOGENATED ALIPHATIC GASEOUS COMPOUND UNDER PRESSURE, A VALVE FOR RELEASING THE CONTENTS OF THE CONTAINER, A NOZZLE MEMBER ATTACHED TO SAID VALVE, SAID NOZZLE MEMBER TERMINATING IN A RESTRICTIVE ORIFICE, SAID RESTRICTIVE ORIFICE HAVING A RATIO OF ORIFICE LENGTH TO ORIFICE DIAMETER OF 0.5 TO 10 SO THAT SAID EXTINGUISHER HAS A RATE OF DISCHARGE PER ORIFICE CROSS-SECTIONAL AREA OF 1,400 TO 3,000 GRAMS PER SECOND PER SQUARE CENTIMETER, A HORN MEMBER ATTACHED TO SAID NOZZLE MEMBER, SAID HORN MEMBER HAVING A RATIO OF HORN LENGTH TO HORN DIAMETER OF 2.6 TO 30 AND A RATIO OF HORN DIAMETER TO ORIFICE DIAMETER OF 2.9 TO 12 SO THAT SAID EXTINGUISHER HAS A RATE OF DISCHARGE PER HORN CROSS-SECTIONAL AREA OF 20 TO 185 GRAMS PER SECOND PER SQUARE CENTIMETER, WHEREBY OPENING THE VALVE CAUSES THE LIQUIFIED HALOGENATED ALIPHATIC GASEOUS COMPOUND TO PASS THROUGH SAID RESTRICTIVE ORIFICE AND BE EXPELLED FROM SAID HORN AS A FIRE SMOTHERING GAS. 